MFC r292066, r292069, r293708, r294027, and r294358, mostly to vdev_geom.c

r292066 | asomers | 2015-12-10 14:46:21 -0700 (Thu, 10 Dec 2015) | 25 lines

During vdev_geom_open, require that the vdev guids match the device's label
except during split, add, or create operations. This fixes a bug where the
wrong disk could be returned, and higher layers of ZFS would immediately
eject it again.

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c:

o When opening by GUID, require both the pool and vdev GUIDs to
  match.  While it is highly unlikely for two vdevs to have the same
  vdev GUIDs, the ZFS storage pool allocator only guarantees they
  are unique within a pool.

o Modify the open behavior to:
  - If we are opening a vdev that hasn't previously been opened,
    open by path without checking GUIDs.
  - Otherwise, open by path and verify GUIDs.
  - If that fails, search all geom providers for a device with
    matching GUIDs.
  - If that fails, return ENOENT.

r292069 | asomers | 2015-12-10 17:04:13 -0700 (Thu, 10 Dec 2015) | 6 lines

Change an important error message from ZFS_LOG to printf

r293708 | asomers | 2016-01-11 15:15:46 -0700 (Mon, 11 Jan 2016) | 16 lines

Fix importing l2arc device by guid

After r292066, vdev_geom verifies both the vdev and pool guids of device
labels during open. However, spare and l2arc devices don't have pool guids,
so opening them by guid will fail (opening by path, when the pathname is
known, still succeeds). This change allows a vdev to be opened by guid if
the label contains no pool_guid, which is the case for inactive spares and
l2arc devices.

r294027 | asomers | 2016-01-14 11:19:05 -0700 (Thu, 14 Jan 2016) | 14 lines

Fix race condition involving ZFS remove events

When a ZFS drive disappears, ZFS sends a resource.fs.zfs.removed event to
userland. A userland program like zfsd(8) can use that event, for example to
activate a hotspare. The current code contains a race condition: vdev_geom
will sent the sysevent _before_ spa.c would update the vdev's status,
causing userland processes to see pool state that does not reflect the
device removal. This change moves the sysevent to spa.c, closing the race.

r294358 | asomers | 2016-01-19 16:16:24 -0700 (Tue, 19 Jan 2016) | 10 lines

Quell harmless CID about unchecked return value in nvlist_get_guids.

The return value doesn't need to be checked, because nvlist_get_guid's
callers check the returned values of the guids.